Fats are important to infants for 3 reasons.
Firstly, due to their high rate of growth, an infant’s energy needs are much greater than those of an adult. Fat is an important source of energy and provides more than twice as much per gram as protein and carbohydrate.
Secondly, it provides substances like prostaglandins as well as the fat-soluble vitamins A, D, E and K.
And thirdly, it insulates. New-born babies have very little insulation and because they have a large surface area compared to body-mass, they can lose heat rapidly. To overall body fats, the ratio of subcutaneous fat in adults is over twice that of infants1. The subcutaneous layer of fat that is found just below the skin acts as insulation and dietary fats play a key role in developing this.
Fat molecules are triglycerides that are made up of a glycerol stem with three positions to which fatty acids bind. There are a number of fatty acids and they can be classified in different ways.
Fatty acids with double bonds are known as unsaturated. Fatty acids without double bonds are known as saturated. Saturated fatty acids like palmitic acid are a source of energy and solid in nature. Unsaturated fatty acids like linoleic acid and arachidonic acid are involved in cell integrity, nerve conduction and brain development.
Essential fatty acids can’t be synthesized by the body.
Non-essential fatty acids can be synthesized by the body.
Conditionally-essential fatty acids can sometimes be synthesized by the body.
Short Chain Fatty Acids (SCFA) are fatty acids with aliphatic tails of fewer than 6 carbons.
Medium Chain Fatty Acids (MCFA) are fatty acids with aliphatic tails of between 6-12 carbons.
Long Chain Fatty Acids (LCFA) are fatty acids with aliphatic tails of more than 12 carbons.
Breast milk contains two important LCFAs. These are the Omega 6 fatty acid, arachidonc acid (AA) and the Omega 3 fatty acid docosahexanoic acid (DHA)2, These play an important role in the development of the brain, eyes and nervous system3,4.
Term infants can synthesize AA and DHA from their precursors, linoleic and a-linoleic acid but Codex and ESPGHAN standards do recommend their inclusion in infant formulas for premature babies.
1. Blackburn ST. Maternal, fetal and neonatal physiology: a clinical perspective. Saunders Elsevier 2007; 706.
2. Birch EE, et al. Visual acuity and the essentiality of docosahexaenoic acid and arachidonic acid in the diet of term infants. Pediatr Res 1998; 44: 201-209.
3. Fleith M, Clandinin MT. Dietary PUFA for preterm and term infants: review of clinical studies. Crit Rev Food Sci Nutr 2005; 45(3): 2005-29.
4. Willatts P et al. Effect of long-chain polyunsaturated fatty acids in infant formula on problem solving at 10 months of age. Lancet 1998;352(9129): 688-91.